Análisis molecular de Trypanosoma cruzi en sangre de piches (Zaedyus pichiy)

Armadillos are considered important reservoir hosts for Trypanosoma cruzi, the causative agent of Chagas disease. The first report of T. cruzi infection in pichis (Zaedyus pichiy), a small armadillo species endemic to central Argentina and Chile, dates back to 1935. However, more recent reports on T. cruzi in this species are scarce. The objective of this study was to assess T. cruzi infection and parasite load in Z. pichiy from Mendoza Province, an area endemic to human Chagas disease. Blood samples were obtained in 2014–2016 from pichis from Lavalle (low Monte), Malargüe (Patagonian steppe), and San Carlos (ecotone) departments, Mendoza Province, Argentina. The detection and quantification of T. cruzi was performed through qPCR amplification using satellite primers. Of the 265 analyzed samples, 201 (76%) were positive for T. cruzi. Parasite loads varied between < 0.1–55.8 parasite-equivalents/mL (par-eq/mL), with a median of 1.1 par-eq/mL in quantifiable samples. The prevalence was similar in Malargüe and Lavalle (85–94%), but significantly lower in pichis from San Carlos (50%). Animals from Lavalle captured after hibernation had significantly higher parasite loads (median 2.0 par-eq/mL). In Malargüe, T. cruzi infection and parasite loads were significantly lower before than after hibernation in 2016. The high prevalence and low median parasite load suggest a chronic and persistent infection of T. cruzi in pichis. Regional differences and a marked increase in precipitation during 2015–2016 could have influenced annual and seasonal infection rates of this vector-borne disease.

犰狳被视为锥虫属（Trypanosoma cruzi）的重要储存宿主，该属为查加斯病（Chagas disease）的致病因子。关于锥虫属感染在小型犰狳物种（Zaedyus pichiy）中的首次报告，该物种为阿根廷和智利中部的特有物种，可追溯至1935年。然而，关于该物种中锥虫属感染的近期报告较为罕见。本研究旨在评估来自门多萨省（Mendoza Province）的Z. pichiy中锥虫属感染及其寄生虫负荷，门多萨省为人类查加斯病的流行区。2014年至2016年间，从阿根廷门多萨省拉瓦列（低蒙泰）、马拉瓜埃（巴塔哥尼亚草原）和圣卡洛斯（生态过渡区）部门的犰狳中采集血液样本。通过使用卫星引物进行qPCR扩增，对锥虫属进行了检测和定量。在分析的265个样本中，201个（占76%）检测到锥虫属阳性。寄生虫负荷介于<0.1–55.8寄生虫当量/mL（par-eq/mL），可量化样本的中位数为1.1 par-eq/mL。在马拉瓜埃和拉瓦列，感染率和寄生虫负荷相似（85–94%），但在圣卡洛斯的犰狳中显著降低（50%）。在拉瓦列捕获的经过冬眠的动物，寄生虫负荷显著升高（中位数为2.0 par-eq/mL）。在马拉瓜埃，2016年前后，锥虫属感染和寄生虫负荷在冬眠前后显著降低。高感染率和低中位寄生虫负荷表明，锥虫属在犰狳中的感染具有慢性且持续的特质。区域差异以及2015–2016年间降水量的显著增加可能影响了该虫媒疾病的年度和季节性感染率。